KR101613741B1 - Low profile flexible cable lighting assemblies and methods of making same - Google Patents

Abstract

A cable light emitting assembly (10) comprising a flexible electrical cable (14, 47) and an LED (43). The electrical insulator of the electrical cable has a portion removed to expose at least one surface mounting site on the surface of the conductor (45) of the flexible electrical cable (47). The two lengths of conductors 59 and 61 are electrically insulated to form at least two electrically insulated surface mount regions that are electrically insulated from each other. The LED 43 is surface mounted to the conductor 45. A solder joint 67 is formed between one of the positive electrode leads 55 of the light emitting diode and the electrically insulated surface mounting portion 61. Another solder joint 69 is formed between the negative electrode lead 57 of the light emitting diode and another electrically insulated surface mounting region 59. At least a certain length of the LED 43 and the flexible electric cable 47 on which the LED is surface-mounted are encapsulated with the polymer molding material 49.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a flexible light emitting diode (LED)

The present invention relates to a cable electroluminescent assembly, and more particularly to a flexible electrical cable electroluminescent assembly using a light emitting diode (LED), and more particularly to a flat flexible cable electroluminescent assembly having LEDs encapsulated with a polymeric molding material, .

Light emitting diodes (LEDs) are used in light emitting assemblies. For example, one or more LEDs have been attached to a printed circuit board. Such a light emitting assembly disclosed in U.S. Patent Application Publication No. 2007/0121326 discloses a light emitting assembly that is a plurality of electrically attached to a printed circuit board that is overmolded with a highly thermally conductive material (e.g., by insert molding) Of LEDs. These multiple circuit board light emitting assemblies may be electrically connected to one or more conductors of an insulated flexible electrical cable to form a light emitting string. Each of these LED circuit board light emitting assemblies is connected using a pair of insulator moving connectors electrically connected to the electrical conductors of the lower electrical cable, moving the electrical insulator.

The present invention is an improved invention of such a conventional light emitting assembly and a method of manufacturing the same.

According to one aspect of the present invention, a method of manufacturing a cable light emitting assembly is provided. The method includes providing a relatively fragile electronic device such as a flexible electrical cable and, for example, a light emitting diode (LED). The flexible electrical cable includes a conductor insulated by an electrical insulator. When the relatively weak electronic device is a light emitting diode (LED), the LED includes a light emitting die mounted on the heat slug and electrically connected to the positive lead and the negative lead. The method also includes removing at least one surface-mount region on the surface of the conductor of the flexible electrical cable by removing a portion of the electrical insulator, and forming at least two electrically isolated surface- Lt; RTI ID = 0.0 > electrically < / RTI > LEDs form a solder joint between one of the electrically-insulated surface-mount regions of the light-emitting diode and the cathode lead of the light-emitting diode, and another solder joint between the lead of the light-emitting diode and the other electrically- Lt; / RTI > The polymeric molding material is injection molded (e.g., insert injection molded) to encapsulate at least a portion of the length of the flexible electrical cable on which the LED and light emitting diode are to be surface mounted. The polymeric molding material is injection molded at a sufficiently low injection pressure to keep the LED from moving and not to damage (e.g., breakage or crack) any solder joints. In addition, at least a portion of the light emitting die of the light emitting diode is kept exposed (i.e., not covered with the polymer molding material) such that the light emitted from the LED is an illuminating visible light.

The flexible electrical cable may be a flat flexible electrical cable or FFC and the cable may comprise a plurality of spaced apart conductors insulated from each other by being separated and coated, for example, in an electrical insulator (e.g., an electrically insulating polymeric material) do. Preferably, the conductor has a generally rectangular cross section and is relatively flat. The desired amount of electrical insulator may be removed by any suitable process, including, for example, laser cutting. Depending on how many electronic devices are surface mounted on the cable and how these electronic devices operate (i. E., The desired electrical circuit design and end use), a number of surface mount locations on one or more of the conductors of the flexible electrical cable It may be desirable to remove a portion of the electrical insulator to expose. One or more of the conductors can each be isolated to two or more electrically insulated surface mount regions, which can be removed by removing portions of the affected conductor (e.g., using a mechanical die, laser, etc.) Cut or punched). It is desirable to surface mount the light emitting diode or any other electronic device to the conductor by forming a solder joint using the solder paste. The use of solder paste allows the solder joint to be formed quickly and the solder flow temperature to be relatively low. In order to encapsulate (i.e., overmold) a desired length of the electronic device and the flexible electrical cable, it is desirable to insert injection molding the thermoplastic polymer molding material. Preferably, this length of the enclosed cable comprises any exposed mounting area and any solder joints.

The method may further include the step of soldering the heat slug of the light emitting diode to the mounting site of the conductor on which the cathode lead or the anode lead is soldered. In addition, the removing step includes sufficiently removing the electrical insulator so that the heat slug can be sufficiently soldered onto the exposed mounting area of the conductor, wherein the method further comprises the steps of: The method may further include the step of soldering the heat slug of the diode. In this way, the conductor can act as a heat sink for the LED through the heat slug.

The enclosed length of the flexible electrical cable preferably prevents the flexible electrical cable from flexing or bending to such an extent that it will damage (e.g., break or crack) any solder joint joining the light emitting diode to the conductor It is stiff enough and not flexible. The enclosed length of the flexible electrical cable may preferably include a protruding protective ridge (e.g., a continuous or discontinuous ridge of polymeric molding material) formed around the exposed portion of the light emitting die of the light emitting diode, The protruding protection ridge has an upper edge that is at least flush with or extends above the uppermost side of the light emitting diode.

According to another aspect of the present invention, there is provided a cable light emitting assembly made in accordance with any method in accordance with the present invention.

According to a further aspect of the present invention there is provided a cable light emitting assembly comprising a flexible electrical cable and a relatively fragile electronic device such as, for example, a light emitting diode (LED). The flexible electrical cable includes a conductor insulated by an electrical insulator. When the relatively weak electronic device is a light emitting diode (LED), the LED includes a light emitting die mounted on the heat slug and electrically connected to the positive lead and the negative lead. The electrical insulator is removed to expose at least one surface mount area on the surface of the conductor of the flexible electrical cable. The two lengths of conductor are electrically insulated to form at least two electrically insulated surface mount regions that are electrically insulated from each other. The LED is surface mounted on the conductor. A solder joint is formed between the positive electrode lead of the light emitting diode and one of the electrically insulated surface mount regions. A different solder joint is formed between the cathode lead of the light emitting diode and the other electrically insulated surface mounting region. At least a portion of the length of the flexible electrical cable where the LED and the LED are surface mounted is encapsulated by an injection molded polymeric molding material. Preferably, each solder joint is made using a solder paste. In addition, a sufficient portion of the LED's light emitting die is exposed (i.e., not covered by the polymeric molding material) so that the light emitted from the LED is an illuminating visible light.

BRIEF DESCRIPTION OF THE DRAWINGS The invention may be better understood with reference to the accompanying drawings, wherein like parts are designated with like reference numerals throughout the several views.
≪ 1 >
1 is a perspective view of a thin flexible cable emitting assembly according to an embodiment of the invention.
2A and 2B,
Figures 2a and 2b are plan views of one embodiment of an upper and a lower die half for insert injection molding an LED surface mounted on an FFC in accordance with the principles of the present invention.
3A and 3B,
Figures 3a and 3b are plan views of one embodiment of an upper and a lower die halves for insert injection molding an electrical switch surface mounted on an FFC in accordance with the principles of the present invention.
<Fig. 4>
4 is a cross-sectional view of an overmolded surface-mounted LED on a conductor of a flat flexible electrical cable in accordance with one embodiment of the present invention.
5,
5 is a cross-sectional view of another LED having a surface mounted and overmolded protective lens on a conductor of a flat flexible electrical cable in accordance with another embodiment of the present invention;

1, an embodiment of a thin flexible cable light emitting assembly 10 in accordance with the present invention includes a plurality of light emitting diode (LED) assemblies 14 electrically mounted on a flat flexible electrical cable (FFC) (12). Each LED assembly 12 includes a light emitting diode (LED) 43 and an optional resistor (not shown), which are preferably attached to one or more conductors 16 of the FFC (e.g., using a solder paste ), And is encapsulated together on the FFC 14 of the corresponding length through the shaped polymeric material 18. The FFC 14 may be made of a thermoplastic material. The conductor 16 is electrically connected to a power source (not shown), for example, by an electrical on / off switch (not shown).

One embodiment of a method of manufacturing a cable light emitting assembly according to the present invention utilizes a series of stations in which operations or steps of the manufacturing process are performed at each station. In the initial trim station, the FFC of the desired length is cut from the FFC spool. This length of FFC is removed by laser cutting in the laser station to sufficiently expose the underlying conductor surface to provide the necessary parts for surface mounting LEDs and optional resistors (not shown) of each LED assembly to be mounted on the FFC Cable insulation portions. And one or more openings are formed through the desired conductors of the FFC according to a given electrical circuit design using, for example, mechanical die punching at the punching station. Optionally, the punching station work can be carried out prior to laser station work. And a desired amount of solder paste is dispensed onto each surface mount area at the solder dispensing station. Each LED, and any other electronic device to be soldered, is soldered onto a surface mount region where the corresponding solder paste is coated at the component placement station. The solder reflow station is operated in accordance with the desired solder reflow time and temperature profile so that each solder paste deposit can flow to form a solder joint between each electronic device and the corresponding surface mount region. The LEDs and optional resistors are encapsulated in a polymeric molding material in a first overmolding station using conventional insert molding equipment. Further details of this shaping operation are discussed in detail below. Any other electronic device (e.g., connector, switch, etc.) may likewise be enclosed in the same or similar overmoulding station. It is contemplated that the above-described method may be modified to include additional manufacturing stations or fewer manufacturing stations depending on the design of the particular cable light emitting assembly being manufactured.

Referring to FIGS. 2A and 2B, one embodiment of the upper die half 21 and the lower die half 23 is shown for insert injection molding an LED surface mounted on an FFC. The upper die half 21 and the lower die half 23 form an inlet 22 for injecting the polymeric molding material when they are combined and each die half 21, 24b, 24c, 24d and 26a, 26b, 26c, 26d, respectively, for cooling sections 21, 23 to a desired temperature. Each die half 21, 23 includes a corresponding hollow half 28, 30 which, when combined, defines the dimensions of the molded polymeric material that encapsulates the LED assembly 12 1). The upper die halves 21 may be formed of silicon or other rubber type material disposed in a corresponding die cavity 27 formed in, for example, the upper die half 21 to seal and protect the LED die during the insert molding process And an elastomeric seal 25 made.

The seal 25 and the cavity 27 are designed to prevent the polymer molding material from being molten in the light emitting portion of the sealed LED and to form a protective ridge of the molding material around the light emitting portion of the LED or other protective structure And dimensions have been determined. 4, for example, the seal 25 has a plane that contacts the surface 51 of the LED 43 to seal it, and is smaller than the inner diameter of the cavity 27 And is a general disk shape having an outer diameter. The periphery edge of the seal 25 is designed and dimensioned to form an annular ridge 71 about the exposed surface 51 of the LED 43 when combined with the shape of the corresponding cavity 27 4). An additional rubber seal 29, 31 made of, for example, silicone or other rubber-type material is disposed in the corresponding cavity of the upper die half 21, so that at either end of the die halves 21, Can be sealed to prevent the molding material from being pushed around the periphery 14 (shown by dotted lines).

When the die halves 21, 23 are assembled around an LED-mounted FFC for insert molding operation, each seal 25, 29, 31 has a constant thickness, eventually applying a sufficiently high compressive force to the LED and FFC , And seals (25, 29, 31) compressing the molten molding material to block passage from the sealed area. The die cavities 28 and 30 formed by the cavity halves 28 and 30 are filled with the polymeric molding material at relatively low pressures since the elastomeric material is used for the seals 25, 25, 29, 31). At the same time, there is no possibility that the LED and FFC will be damaged during the molding process due to the elastomeric nature of the seals 25, 29, 31 (specifically the seal 25). In addition, if a stiffer material (e.g., a metal forming material) is used for the seals 25, 29, 31, it may be necessary to use a higher compressive force to prevent leakage of the polymeric molding material. Combining harder materials with higher compressive forces increases the likelihood that the LED and, to a lesser degree, the FFC will be damaged during the injection molding operation. Each of the die halves 21, 23 includes a plurality of exhaust channels 32 to avoid trapping bubbles in the die during the injection molding operation. The seal 25, 29, 31 would not be able to prevent the molding material from leaking from the die cavities 28, 30 if the polymer molding material was injected into the mold cavity at normal injection molding pressures.

3A and 3B, an upper die half (not shown) for insert injection molding an electrical switch (not shown) surface mounted on the FFC 14 (shown in phantom) in a manner similar to that described above for the LED 43 One embodiment of the portion 33 and the lower die half 35 is shown. Each of the die halves 33 and 35 includes corresponding cavity halves 38 and 40 which, when combined, define the size of the molded polymeric material enclosing the electrical switch. The upper die half 33 and the lower die half 35 form an inlet 22 for injecting the desired polymer molding material when they are combined and each die half 33, 24b, 24c, 24d and 26a, 26b, 26c, 26d, respectively, for cooling the halves 33, 35 to the desired temperature. The upper die half 33 includes, for example, an elastomeric seal 37 made of silicone or other rubber-type material disposed in a corresponding cavity. The seal 37 is of a predetermined size in the form of a donut or O-ring for sealing and protecting the actuating element of the electrical switch (for example a push button), the actuator being arranged in the hole of the seal 37 . Each of the die halves 33 and 35 also includes a corresponding elastomeric seal 39 made of silicone or other rubber type material for sealing the FFC 14 at one end of the die halves 33 and 35, , 41). In the illustrated embodiment,

Like the die halves 21 and 23, when the die halves 33 and 35 are assembled around a switch mounted FFC for an insert molding operation, each seal 37, 39 and 41 has a constant thickness (37, 39, 41) which compresses the molten molding material to block passage of the molten molding material from the sealed area by applying a sufficiently high compressive force to the switch and the FFC. The die cavities 38 and 40 formed by the cavity halves 38 and 40 are filled with the polymeric molding material at relatively low pressures since the elastomeric material is used for the seals 37, 37, 39, 41). At the same time, the elastomeric nature of the seals 37, 39, 41 is unlikely to damage the switch and the FFC during the molding process. In addition, if a more rigid material (e.g., a metal forming material) is used for the seal 37, 39, 41, it may be necessary to use a higher compressive force to prevent leakage of the polymeric molding material. The combination of stiffer materials and higher compressive forces increases the likelihood of damage to the switch and, to a lesser extent, the FFC during the injection molding operation. Each of the die halves 33, 35 includes a plurality of exhaust channels 32 to avoid trapping bubbles in the die during the injection molding operation. 39, 41 will not be able to prevent the molding material from leaking out of the die cavities 28, 30 if the polymeric molding material is injected into the mold cavity at normal injection molding pressures.

Referring to Fig. 4, there is shown an LED 43 that is surface-mounted on a flat (i.e., rectangular cross-section) conductor 45 of a flat flexible electrical cable 47 and encapsulated by a polymeric molding material 49. The LED 43 includes a light emitting die (not shown), a heat slug 53, a cathode lead 55 and a cathode lead 57 that emit light through the surface 51. The conductors 45 are separated into two electrically insulated lengths 59, 61 by punched openings 63. As shown in Fig. The heat slug 53 and the positive electrode lead 55 are individually electrically connected to the conductor length portion 61 by the respective solder joint portions 65 and 67. The negative electrode lead (57) is electrically connected to the conductor length portion (59) by the solder joint (69). The molding material 49 preferably includes an annular protective ridge 71 around the surface 51. The protection ridge 71 protrudes and the upper edge is at least flush with or extends above the light emitting surface 51.

5, there is shown another LED 73 that is surface-mounted on a flat (i.e., rectangular cross-section) conductor 45 of a flat flexible electrical cable 47 and encapsulated by a polymeric molding material 49. The LED 73 includes a light emitting die (not shown), a heat slug 53, a cathode lead 55, and a cathode lead 57 that emit light through a protective lens 75. The conductors 45 are separated into two electrically insulated lengths 59, 61 by punched openings 63. As shown in Fig. The heat slug 53 and the positive electrode lead 55 are individually electrically connected to the conductor length portion 61 by the respective solder joint portions 65 and 67. The negative electrode lead (57) is electrically connected to the conductor length portion (59) by the solder joint (69). The molding material 49 preferably includes an annular protective ridge 71 around the protective lens 75. The protection ridge 71 is protruded and has an upper edge at least at the same height as the emission lens 75 or extending thereabove.

Exemplary light emitting diodes (LEDs) that may be used in accordance with the present invention include chips manufactured from OSRAM Opto Semiconductors GmbH (www.osram-os.com), each of Wernerbergstrasse 2, Reengensburg D-93049, Germany LW M5SM Golden DRAGON®, Chip Level Conversion LED, LW M5KM Golden DRAGON® ARGUS®, Chip Level Conversion LED, and LD-W5AP, LB W5AP or LT W5AP Diamond DRAGON®, chip level conversion LEDs, But is not limited thereto.

A typical flat flexible electrical cable (FFC) that can be used in accordance with the present invention is a flat flexible electrical cable sold by LEONI Kabel GmbH (www.leoni-cable.com), Stybars-La-Zeese 5, Lot 91154 But are not limited thereto. The FFC includes three spaced apart copper conductors that are covered by the electrically insulating polymeric material PBT. In order to avoid this FFC insulation from being damaged in relation to heat, soldering the components onto the FFC using a relatively low temperature solder paste (e.g., a solder paste that forms a solder joint at a lower temperature than the comparative solid solder) Is preferable.

Typical types of solder pastes that may be used in accordance with the present invention include NCLR of non-clean distributed solder paste made by EFD Inc. of Blackstone Valley Place, Lincoln, RI, 02865, Series SolderPlus &lt; (R) &gt;. These solder pastes are characterized by low flux residue and excellent wettability, which can be relatively quickly and easily dispensed at room temperature and can be dispensed at nominally about 3 minutes at a relatively low temperature between about &lt; RTI ID = 0.0 &gt; The solder joint can be formed in a relatively short time. Although it is known to be used to form solder joints on circuit boards, it has been found that such distributed solder paste is not preferred for use in flexible (e.g., stiff) electrical cables. The solder joint formed by using the solder paste is relatively weak when subjected to a bending stress such as a kind of bending stress which is received at the solder joint formed when the LED is mounted on a conductor of a flexible cable such as an FFC, It was found to be easy. In order to combine the use of the solder paste and its advantage with the flexible electrical cable, it is possible to overcome the drawbacks of the found solder paste by molding over a flexible cable of a certain length on the soldered LED and the side on which the LED is soldered &Lt; / RTI &gt;

Typical insert-forming materials that can be used in accordance with the present invention include, but are not limited to, hot melt resins available from Bostik, Inc. of Middleton, Massachusetts, USA. Such resins include BOSTIK® LPM 245 adhesives, BOSTIK® LPM 915 adhesives, and BOSTIK® LPM 917 adhesives. Other suitable resins and materials may include, for example, HENKEL® / LOCTITE® macromelt materials such as HENKEL® OM673, 678, 682 and / or 687 Macromelt.

Conventional insert molding techniques generally involve extruding a thermoplastic polymer molding material into a pair of overlapping mold die halves under an injection pressure exceeding 6895 mm (1000 pounds per square inch (psi)). This molding operation is known to utilize the pressure to inject the thermoplastic polymer molding material into the mold at a high range of from about 3000 psi to about 7000 psi. In order to prevent flashing of the molding material between the die halves of conventional molds, the die halves are pressed together under clamping pressure which can significantly exceed the molding material injection pressure. It has been found that such conventional injection molding techniques can have undesirable consequences when used, for example, for molding onto relatively delicate electronic devices such as LEDs surface-mounted to the conductors of flexible cables using solder joints. This is especially the case with solder joints made of solder paste.

When injected into the mold cavity under such a high pressure, the force exerted by the molded material injected against the surface-mounted LED can destroy some or all of the solder joints, Partially or completely moving in a surface mounted position and losing some or all of the electrical connection to the flexible cable. The solution to this problem is less than 600 pounds per square inch (pounds per square inch), preferably less than 800 psi, less than about 600 psi, less than about 400 psi, and preferably about 827.4 pounds per square inch It has been discovered that molding involves covering such surface-mounted LEDs and flexible cables using relatively low injection molding pressures ranging from 120 psi to about 400 psi. Due to this low injection molding pressure, a low clamping pressure can thereby be used between the two mold die halves without flashing of the molding material between the die halves. In an insert-molded electronic device in which it is necessary to keep a specific surface (e.g., the light emitting surface of an LED, or the on / off button of an electrical switch) exposed after the device is insert molded, (For example, made of an elastomeric polymeric material such as silicone rubber) can be used due to the die half clamping pressure that follows, so that such exposed surfaces can be sealed against flashing of the molding material. The injection molding die is generally made of a metal, such as tool steel, for example. A resilient mold die component that elastically seals to prevent flashing of the molding material can be very important when used to protect exposed surfaces of relatively delicate electronic devices, such as LEDs. If such a typical die-mold metal material was used to seal such a surface that would be kept in an exposed state, the clamping pressure needed to prevent flashing could damage the surface of the electronic device that would block flashing.

The light emitting portion of the LED which needs to be kept in the exposed state is Da. LEDs are relatively fragile and are more likely to withstand the high pressures exerted by metal mold die components as well as the clamping pressures exerted by resilient mold die components (eg, silicone rubber) than the same clamping pressure. Using a resilient mold die component in this way allows the mold die to compensate for large variations in dimensional tolerances of the electronic device. If a mold die component made of metal or other stiff and rigid material is used to seal the surface of the electronic device to be maintained in an exposed state, damage to the electronic device of greater dimensions than the mold is designed to accommodate, There will be a greater likelihood that the exposed surface of an electronic device with a smaller dimension than that designed to be sealed sufficiently.

The preferred results were obtained using SolderPlus® 42 NCLR distributed solder paste to electrically couple the LEDs to the conductors of the flexible electrical cable. A measured amount of solder paste was dispensed at each desired solder joint location on a previously exposed conductor surface using one cycle time per launch of about 1.5 seconds at room temperature (i.e., about 20 ° C). After the solder paste is dispensed and the LEDs are placed in the surface mount position, the solder paste is melted and flowed to allow the solder paste to flow and react, so as to form a solder joint that joins the LEDs to the flexible cable conductor and electrically connects them. The solder paste was exposed to the profile. The reflow time-temperature profile begins with a pre-heating which linearly rises from about 30 ° C to about 100 ° C in about 60 seconds, followed by a heat sink beginning at about 100 ° C for about 75 seconds and rising linearly to about 130 ° C followed by a heat soak followed by an activation step starting at about 130 ° C for about 20 seconds and rising linearly to about 138 ° C and continuing from about 138 ° C for about 45 seconds to a maximum temperature of about 178 ° C Followed by an initial cooling step starting at about 178 DEG C and down linearly to about 138 DEG C followed by a final cooling step starting at about 138 DEG C and linearly falling to about 30 DEG C . The entire cooling process (i.e., the last two steps) took about 40 seconds.

The desired results were also obtained by insert molding these surface-mounted LEDs using a hot melt resin available under the name BOSTIK® LPM 917 adhesive from Bostik, Inc. of Middleton, Massachusetts, USA. The thermoplastic resin material was extruded at a temperature of about 225 占 폚, at an injection pressure in the range of about 220 to 280 psi and in a range of about 12 to 15 seconds for one cycle time molding each LED. This low injection molding pressure allowed the use of clamping pressures of less than about 800 psi (5516 MPa) between the two mold die halves.

It has been found desirable to use a flat flexible electrical cable sold by LEONI Kabel GmbH as part number 67403000A. The FFC has three conductors, with a total width of 13.50 mm ± 0.15 mm. Each conductor is relatively flat and has a generally rectangular cross-section. Each conductor has a thickness of about 0.1 mm. The center conductor is about 6.62 mm in width, and the two outer conductors are about 1.54 mm in width. A central conductor was used to surface mount the LED. It is desirable to use a wider center conductor to surface mount the LED. Although additional widths of central conductors are not required to provide sufficient electrical connection to the LEDs (i.e., to handle the current needs of the LEDs), due to the additional width, the center conductor conducts heat generated by its operation from the LEDs It can work better as a heat sink. Further, the wider the center conductor, the larger the target surface area that the solder joint can be formed. The FFC has a minimum bending radius of about 0.45 mm and an operating temperature rate of about 125 ° C. for 3000 hours.

The above-mentioned DRAGON &lt; (R) &gt;, manufactured by OSRAM Opto Semiconductors GmbH, in which the heat slug is electrically connected to the cathode lead In LEDs and other LEDs, the heat slug can be soldered directly to the FFC conductor. This facilitates the heat sink function of the conductor and simplifies the manufacturing process. In an LED in which the heat slug is electrically isolated from the cathode lead and the cathode lead, an adhesive having thermal conductivity and electrical insulation can be used to attach the LED heat slug to the FFC conductor. An example of such a curable adhesive is a high adhesive thermally conductive adhesive transfer tape manufactured by Product Number Series 8800 from 3M Company, St. Paul, Minnesota, USA. The preferred results were obtained using a 3M Company transfer tape 8810.

Claims (15)

A method of manufacturing a cable light emitting assembly,
Providing a flexible electrical cable comprising a conductor insulated by an electrical insulator;
Providing a light emitting diode mounted on the heat slug and including a light emitting die electrically connected to the positive electrode lead and the negative electrode lead;
Removing a portion of the electrical insulator to expose at least one surface mount portion on the surface of the conductor of the flexible electrical cable;
Electrically insulating the two lengths of the conductor to form at least two electrically isolated surface mounting regions electrically insulated from each other;
A solder joint is formed between the positive lead of the light emitting diode and one of the electrically insulated surface mount portions and another solder joint is formed between the negative lead of the light emitting diode and the other portion of the electrically isolated surface mount portion, To a conductor; And
Molding a polymeric molding material to encapsulate the light emitting diode and a flexible electrical cable of a predetermined length on which the light emitting diode is surface mounted,
Wherein the injection molding of the polymeric molding material does not damage any of the solder joints and at least a portion of the light emitting die of the light emitting diode is kept sufficiently exposed to release the illumination light. A method of manufacturing a cable light emitting assembly,
Providing a flexible electrical cable comprising a conductor insulated by an electrical insulator;
Providing a light emitting diode mounted on the heat slug and including a light emitting die electrically connected to the positive electrode lead and the negative electrode lead;
Removing a portion of the electrical insulator to expose at least one surface mount portion on the surface of the conductor of the flexible electrical cable;
Soldering the heat slug of the light emitting diode to at least one surface mounting area of the conductor and also brazing the cathode lead or the cathode lead to the at least one surface mounting area. 2. The method of claim 1, wherein said removing comprises removing an electrical insulator sufficient to mount the exposed conductor so that the heat slug can be soldered thereto,
Further comprising the step of soldering the heat slug of the light emitting diode to the mounting site of the conductor on which the cathode lead or the anode lead is soldered. The method according to any one of claims 1 to 3, wherein the forming or soldering of the solder joint is carried out using a solder paste. 4. The method according to claim 1 or 3, wherein the injection molding is performed at an injection molding pressure in the range of 827.4 to 2758 mm. A cable light emitting assembly produced according to the method of any one of claims 1 to 3. In a cable light emitting assembly,
A flexible electrical cable comprising a conductor insulated with an electrical insulator, said electrical insulator having a removal portion that exposes at least one surface mounting site on one side of the conductor, the two length portions of the conductor being electrically Electrically insulated to form at least two electrically isolated surface mount regions insulated; And
A light emitting diode mounted on the heat slug and electrically coupled to the positive lead and the negative lead, the light emitting diode being surface mounted on the conductor, wherein a solder joint is formed between the positive lead and the electrically insulated surface mount region And another solder joint is formed between other portions of the surface mount region that are electrically insulated from the negative electrode lead,
/ RTI &gt;
At least a part of the length of the flexible electric cable on which the light emitting diode and the light emitting diode are surface-mounted is sealed by a polymer molding material, and at least a part of the light emitting die of the light emitting diode, Wherein the light emitting assembly is exposed. In a cable light emitting assembly,
A flexible electrical cable comprising a conductor insulated with an electrical insulator, the electrical insulator having a removal portion that exposes at least one surface mount portion on one side of the conductor; And
And a light emitting diode mounted on the heat slug and electrically connected to the positive lead and the negative lead, wherein the light emitting diode is mounted on the mounting portion of the conductor, to which the positive lead or the negative lead is soldered, Surface mounted to said conductor to be soldered to said slug;
&Lt; / RTI &gt; 9. The cable light emitting assembly according to claim 7 or 8, wherein the forming or soldering of the solder joint is carried out using a solder paste. 8. A cable lighting assembly according to claim 7, wherein the enclosed length of the flexible electrical cable is sufficiently stiff and non-flexible to prevent flexing of the flexible electrical cable to such an extent as to damage the solder joint joining the light emitting diode to the conductor. . delete delete delete delete delete

Images